Foam guns have been used for years to produce multiple plural component foams which typically are made up of iso and resin components. Of course, as used herein, the term foam can be understood to refer to any plural component material requiring mixing. Such products have typically suffered from slight conditions of off-ratio resulting from the lead/lag in flow initialization which in turn causes the initial portion of the shot to be iso (or resin depending on the arrangement) rich. This results from the fact that resin and iso components entered the nozzle at different planes.